Quasar Dust in the Early Universe

March 26, 2010

A Hubble image of a nearby quasar. New Spitzer Space Telescope infrared observations of distant quasars, objects whose light traces an early epoch of the universe (about 12 billion years ago), have discovered that some apparently date from a time before dust had been made, or at least before it was readily available. Credit: NASA Hubble Space Telescope

(PhysOrg.com) -- Quasars are galaxies whose very bright cores are thought to contain massive black holes around which disks are actively accreting matter.

The accretion process releases vast amounts of energy, and as a result quasars are among the most powerful energy sources known. No one knows for sure, however, how these objects form, how they develop in time, or how exactly their stupendous energies are produced. Because they are so bright, quasars can be seen even when they are very far away, and this combination of being both highly energetic and located at cosmological distances makes them appealing to astronomers trying to figure out the nature of galactic center black holes (our own Milky Way has one) and the conditions in the early universe that prompt these monsters to form.

There are about forty quasars known to be so far away that their light has been traveling toward us for over twelve billion years; in other words, their black holes were already glowing brightly when the universe was very young - less than one billion years old. The question is: do they look like nearby quasars, or are they different somehow? CfA astronomer Yue Shen is a member of an international team of twelve astronomers that has concluded that some remote quasars are very different indeed.

Using the Spitzer Space Telescope's sensitive infrared cameras, the scientists observed twenty-one distant quasars to see whether or not they could detect evidence for hot dust; such dust would be expected if there really is a hot accreting disk of material around a black hole. Indeed, hot dust is a characteristic feature of quasars in the local universe.

Remarkably, as the team reports in this week's issue of Nature, two of the quasars in their study show no evidence for hot dust. The implication is that these galaxies are so primitive (in cosmic terms) that there has not been time for them to make dust, presumably either because there has not been time to form enough of the required constituent chemical elements, or because there has not been time to assemble them into dust grains. The results suggest that these objects date from an epoch in the universe when dust was first being made. Dust is a key catalyst in turning atomic gas into the molecules that facilitate stellar birth and evolution, and this new result is significant not only for quasar research, but also for helping understand how the first few generation of stars in the universe came to be.

Related Stories

(PhysOrg.com) -- Astronomers have come across what appear to be two of the earliest and most primitive supermassive black holes known. The discovery, based largely on observations from NASA's Spitzer Space Telescope, will ...

Most of the biggest black holes in the universe have been eating cosmic meals behind closed doors – until now.
With its sharp infrared eyes, NASA's Spitzer Space Telescope peered through walls of galactic dust to uncover ...

A team of Sloan Digital Sky Survey (SDSS-II) scientists, led by Princeton University's Reinabelle Reyes and including astronomers at Penn State, has identified a large number of "hidden quasars" -- supermassive black holes ...

Supermassive black holes found at the centers of distant galaxies undergo huge growth spurts as a result of galactic collisions, according to a new study by astronomers at Yale University and the University of Hawaii. Their ...

Astronomers have found the first clear evidence of a binary quasar within a pair of actively merging galaxies. Quasars are the extremely bright centers of galaxies surrounding super-massive black holes, and binary quasars ...

New data from NASA's Chandra X-ray Observatory may provide clues to how quasars "turn on." Since the discovery of quasars over 40 years ago, astronomers have been trying to understand the conditions surrounding the birth ...

Recommended for you

(Phys.org)—A small team of researchers from the U.S. and Italy has found evidence of a naturally formed quasicrystal in a sample obtained from the Khatyrka meteorite. In their paper published in the journal Scientific Reports, ...

As a cosmic dust magnet, Saturn's C ring gives away its youth. Once thought formed in an older, primordial era, the ring may be but a mere babe – less than 100 million years old, according to Cornell-led astronomers in ...

Scientists on board NASA's flying telescope, the Stratospheric Observatory for Infrared Astronomy, or SOFIA, caught sight of roiling material streaming from a newly formed star, which could spark the birth of a new generation ...

Astronomers have used NASA's Chandra X-ray Observatory and other telescopes to show that a recently-discovered galaxy is undergoing an extraordinary boom of stellar construction. The galaxy is 12.7 billion light years from ...

A professional astrophysicist and an amateur astronomer have teamed up to reveal surprising details about an unusual millisecond pulsar (MSP) binary system comprising one of the fastest-spinning pulsars in our Galaxy and ...

A sad day indeed to see a "scientist" with your credentials feel the need to promote your personal theory through "a U-tube video of "Nellie the Neutron"" that in no way explains (or even mentions) your theory of neutron repulsion. I see this video is to be one of a series, aimed at junior high to high school students (or those with equivalent educations). That you would even associate yourself with others using such tactics, similar to those used by "Electric Universe" and creationist proponents, speaks volumes about your personal integrity. What's next, Nellie the Neutron coloring books?